1. Field of the Invention
The present invention relates to an adjusting device and more particularly, to an improved adjusting device disposed in a chair such that a seat portion and a back portion can be adjusted simultaneously.
2. Brief Description of the Prior Art
A conventional office chair is partially shown in FIG. 1, the chair includes a seat portion disposed on a base frame 90 and a back portion disposed to a post 922 which is slidably received in a bracket 92 which is pivotally engaged to a rear end of the base frame 90 by a first pin 906. The base frame 90 is pivotally engaged to a chair support 912 which has an extending plate 91 extending radially therefrom for a spring 904 disposed between the extending plate 91 and an under surface of the base frame 90 so as to provide a satisfactory feature. A first moving means 94 has one end thereof pivotally connected to the bracket 92 by a second pin 928 and the other end of the first moving means 94 has a first/slot 942, a second moving means 93 having one end thereof pivotally connected to a lug 916 extending from the extending plate 91 and the other end of the second moving means 93 having a second slot 932. A control bar 96 extends through the first slot 942 and the second slot 932, the control bar 96 can fixedly position the first moving means 94 and the second moving means 93 by a rotation action, i.e. the control bar 96 performs as a quick release to control the first moving means 94 and the second moving means 93. Each of the first moving means 94 and the second moving means 93 includes of plurality of plates and each of the plates of the two moving means 94, 93 are alternately overlapped with each other at the respective two ends having the first slot 942 and the second slot 932. An urging element 908 is mounted to the first pin 906 and has two legs respectively contacting against the under surface the base frame 90 and the second pin 928. When operating the control bar 96, the first moving means 94 and the second moving means 93 move freely along the first slot 942 and the second slot 932 respectively so as to adjust the seat portion 902 and the back portion 924. After the desired positions of the seat portion 902 and the back portion 924 have been set, the control bar 96 is re-operated to fixedly position the first moving means 94 and the second moving means 93.
However, when pushing the back portion 924, the seat portion 902 is maintained still unless a force is exerted downwardly to the seat portion 902. Generally, a user adjusts the chair when he/she sits in the chair and, according to the above mentioned description, when the user exerts a force to the back portion 924 the seat portion 902 is maintained still, this puts the user in an unsatisfactory pose and his/her clothing will be pulled upwardly. Therefore, in order to adjust the seat to a desired status, the user has to use two different forces, one is exerted to the back portion 924 from the back of the user and the other force is exerted to the seat portion 902 from the posterior of the user. It is difficult for the user to exert the two forces separately when sitting on the chair.
The present invention intends to provide an improved adjusting device which can adjust the seat portion and the back portion to a desired position simultaneously so as to mitigate and/or obviate the above-mentioned problems.